<template>
  <div>
    <div v-for="(item, index) in arr" :key="item.id">{{ index + 1 + ':' + item }}</div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      arr: ["a", "b", "c", "d"],
    };
  },
};
</script>